This book constitutes the thoroughly refereed post-conference proceedings of the 4th International Conference on Information Security and Cryptology, Inscrypt 2008, held in Beijing, China, in December 2008. The 28 revised full papers presented together with 3 invited talks were carefully reviewed and selected from 183 submissions. The papers are organized in topical sections on digital signature and signcryption schemes, privacy and anonymity, message authentication code and hash function, secure prools, symmetric cryptography, certificateless cryptography, hardware implementation and side channel attack, wireless network security, public key and identity based cryptography, access control and network security, as well as trusted computing and applications.